Have a small drink before you meditate.If it continues - just try to maintain awareness of your meditation object.If your throat is sore/dry during other times of the day it could be symptomatic of a cold.kind regards,

Ben

“No lists of things to be done. The day providential to itself. The hour. There is no later. This is later. All things of grace and beauty such that one holds them to one's heart have a common provenance in pain. Their birth in grief and ashes.” - Cormac McCarthy, The Road

Learn this from the waters:in mountain clefts and chasms,loud gush the streamlets,but great rivers flow silently.- Sutta Nipata 3.725

is it possible you are forcing the breath in and out? if the breath goes in and out with too much force the air will strike the throat and nose in a harsh way and dry it out. i found myself unconsciously forcing on the exhale to create a more clear breath sensation a while back and i didn't even realize i was doing it. also make sure you swallow your spit and dont just let it pool up in your mouth.

"It's easy for us to connect with what's wrong with us... and not so easy to feel into, or to allow us, to connect with what's right and what's good in us."